Limitation of the short-circuit ruggedness of high-voltage IGBTs

In this paper, the destruction mechanism, which limits the short-circuit capability of high voltage IGBTs utilizing N-buffer structures will be described. The failure mechanism was studied using a combination of device simulations and experimental investigations of 3.3 kV, 4.5 kV and 6.5 kV IGBTs. It was found that the limiting short-circuit failure in these IGBTs is caused by a current filamentation mechanism, which is associated to a distortion of the electric field triggered by a positive feedback effect between the carrier drift velocities and the electric field and the resulting potential distribution in the IGBT N-base.